Method of controlling plant growth



" No Drawing.

States METHOD F"CONTI0LINGPLANT GROWTH Ivan C. PopolL -Amblen'Pa, assignor-to PennsaltChemicalsCorporation, Philadelphia, Pa., a corporation. of

Pennsylvania 7 Filed Nov. 15,1961, Ser. No. 152,668 9.Claims. (Cl. 71-23) This invention: deals withanovel method-of. control lingplant life andis CQHCBI'IEdiWlth/thfi .use. of certain psphenylenedi amine derivatives as plant response agents,

. particularly as. herbicides, defoliantsand desiccants.

It .isof great economic and social importance-to develop I new plant response agents. Our improved yields of crops and grains are. due inrl'arge, measure to*the use'of chem ical" plant control methods. These techniques involve not only use of chemicals to control weeds and unwanted vegetation, but also to effect. defoliation, desiccation, etc.

It has now been-found that plant responsesmay effec- 'tivelybe obtained" by using; chemical compounds. derived lfrom N,N"-disu-bstituted psphenylenediamines. particularly, the plantaresponse. agents used inthis invenr tion havesthe' general .formula where R is a: member selected from-the groupofalkyl, cycloalkyl and. aryl .radicals,-.Z isa divalent; hydrocarbon radical, X is ;H1or

and'n is aninteger from Ito 10.

The preparation-ofihese compounds is acliieved'readily T by reaction ofamalkylene. oxide with an N,N'-disubsti-. tuted'.p-phenylenediamine; i.e. a' compound ofstructure 1 Where R is the. same as defineda-bove. The'-p-phenylene-- diamine starting materials are well known andareadily available by variousrmeanszof syn-thesis; see, for. example, US. Patents 2,498,630 and 2,867,604. Examples of -pphenylenedi amines'which may. be used are (1) N,N-

dialkyl-p-phenylenediamines in which. the substituent groups,'which may'betthe same or different, include alkyl radical-s:selectedflfromthe group comprising methyl, ethyl, n-propyl, isopropyl, n.-'butyl,wsec=butyl, tert butyl, .n-amyl, isoamyl, sec-amyl, tert-amyl, n-hexyl, n-octyl, t-octyl, l-ethyl-3-methylpentyl,

l-methylheptyl, n-decyl, n-dodecyL'n-hexadecyl, ootadecyl, tridecyl, and

' like radicals; (2) N,N-dicycloalkyl-p-phenylenediamines in which the subs'tituent groups are the same or different i-suchas N,N-bis-('cyclohexyl)-p?phenylened-iamine, N- g cyclohexyl-N'-methylcyclohexyl-p-phenylenediamine and Ethelike; (3) 'N alkyl N cycloalkyl p phenylenedizamines such as N-methylN--cyclohexyl-p phenylenediamine,' N- I sec-'butyl N'-met.hylcyclohexyl p-phenylenediamine and the like; (4) N-alkyl-N aryl pephenylenediamines where the' alkyl radicals are exemplified by, any of the abovea listed;.alkyl and: cycloalkyl radicals and the aryl radicals are exemplified: by phenyl, t'oliyl,: xy1y1,-nap hthyl,. andthe Y More.

l-methyloctyl,

181-;942 *BatentdiMay-4,' I965 like; and .(5) vl .l ,N '-dia ryl pephenylenediaruineswhere the aryl radicals aretzany of thoserl-isted-mabove. Further specific illustrations of useful;p-phenylenediam-incs are -N-ethyl-N-cyclopentyl, N,N-diphenyl;"N,N'+dinonyl,' N,.- Nfldidodecyl, -N-methyl-N sec-butyl,l N-secbutyl'-N'-isopropyl, N,N-di(1=methyloctyl), N-tolyl-Nf-cyclopentyl, N-phenyl-N'eundecyl", N-phenyLNtatolyl, and. the like.

Theflalkylene oxides which? are; reacted with: the pphenylenediamine: "are- .Welll.knownx compounds and; are exemplified "'by the oxides of. ethylene," propylene: the

isomeric?n butylenes,. isobutylene, .nn-amylenes, styrene,

the isomeric;"methylstyrenes,ifthe isomeric isopropylsty renes, the isomeric. naphthylstyrenes, and-the. like.- Also .useful are .alltylene. oxides such as but'adiene monoxide.

Of "the. abovexalkylene oxides we;,preferrtoluse.thosezhavring the structure where R ishydrogen'or.ahydrocarbon radical containingirom oneto eightcarbonfatoms- 'Thereactiomof the: alkylene; oxide -withpihenylene 'diaminex is: carriedrout readily in accord with known procedures .fori 'alkylene: oxide: condensation reactions. In.

general, the reaction .is. carried out by .simplywsubjecting a: mixtureiof. one-mole: of the p-phenylenediamine audione or; more ":mb'les" of; the. alkylene. oxide :..to reaction at elevatedctemperatures.underautogenousrpressure. Usually the amount; of alkylene- :oxide iwill bei from onemto twenty molespervmoliexof pnphenylene'diamine.v 'lReaction will occur rat: one or?" both*N'-H1 bonds. to I yield the; subunderstood. that: when: less than two" molesof alkylene oxide per-mole. of :p-phenylenediamine. derivative is used more. of the: mono=substitutedicompound:vtlillbe formed together with. asmall amount of the disubstituted product.

. It will be-understoodith'at if one: n is: zerorinv the structure given; above- :then the mono-substituted compounds are represented. *Expressedanother 'way, reaction of-one mole. of'the lalkylene oxide-with; one: mole of the N',N'- disubstituted: p-phenylenediami'ne yields: mainly products havingthestructure where. R ,,Z .anch ni are :Ihe. sameas defined-above: and Xis hydrogen.

The temperature: of ithe.reaction'will;be between about 25 and. 250 "'C., lhCJ'CaCtiOITPI'OCEEGJ iIg more/slowly.v at

I the. lower temperatures. Althoughh:highmpressure' reactionsm'aybe used,-tit sufli'ces: to:.allow reaction to occur under: autogenous pressure. If. desired, solveutt systems .may: be :usedI-and: such" solvents-will; of course,r*be "inert to the reactants and: products. Useful solvents. include the. aromatic hydrocarbons. such benzene; toluene, 4 xylene, etc.;. 'ethers: and. cyclic ethers :(eigtildioxane) tri- ,alkyl'aminesjand: the. like. '-When;;ilower-reaction"itemperatures: are used,1it=is frequently vde'siralbleto; use a a: catalyst andtthese will; 'be inert. basic compounds such as ter' tmines (trimethylamine, pyridine), alkali metal car- :s, and'the like or acidic type catalysts such as HCl,

, as is well known in the art.

compounds as prepared by the above methods are 'ticular value as active ingredients for herbicides; r killing weeds among cultivated plants (i.e. selec- :rbicides) and also for the complete elimination of red plant growth (i.e. nonselective herbicides). The 'esponse agents according to this invention may be ns, suspensions, emulsions ordusts, dependingon sans desired for application. Thus, for example, complete inhibition of plant growth is desired, the may be incorporated in carriers which are toxic its, such as high boiling mineral oils or in hydrot and halohydrocarbon solvents. For selective heruse, however, inert carriers will be preferred. It e-understood, of course, that not all of the com- 5 defined above will have equal plant response ac- Although reference has been made to herbicidal y to illustrate the use of the agents, some agents will imited herbicidal activity, but will be active defolir desiccants. The specific application of the varipes of agents will be apparent from the illustrative les. The preferred agents for use in this invention 1 those where R is alkyl, cycloalkyl, or aryl radicals ting up to about eight carbon atoms, where Z is a it hydrocarbon radical containing two to three caroms, and n is one to four.

detailed techniques of using plant response agents ous formulations are well known in the art. Thus, ample, formulation of the active agents into herand other plant response compositions is taught by in-U.S. Patents Nos. 2,655,444 to 2,655,447. The dusts, solvents, wetting, dispersing and emulsifying for such preparations is also disclosed in US. 417. For example, mineral oil fractions such as me or diesel oil, or coal tar oil and oils of. vegetable mal origin can be used as solvents for solutions can be sprayed directly onto the plants; The acigredients according to this invention are added to )ils direct or with the use of suitable axiliary solsuch as xylene. Solutions in lower boiling or also re expensive solvents such as alcohols, e .g. ethyl or pyl alcohol, ketones such as, e.g. acetone or cycloone, hydrocarbons, e.g. benzene, toluene, xylene, vdronaphthalene or alkylated naphthalenes and chloi hydrocarbons such as tetrachlorethane or ethylene ie are less suitable for direct application but can be ?or combinations with suitable emulsifiers for the :tion of concentrates which can be worked up for us emulsions. ieous application forms are made from emulsions ispersion concentrates by adding water to the subs as such or dissolved in one of the above named ts and are homogeneously incorporated into water, ably by means of wetting or dispersing agents. Exs of cation active emulsifiers or dispersing agents aternary ammonium compounds, examples of anion emulsifying agents are soap, soft soap, long chained tic sulphuric acid monoesters, araliphatic sulphonic long chained alkoxyacetic acids and examples of nic emulsifiers are polyglycol ethers of fatty alcohols tlyethylene oxide condensation products. Also, contes can be produced consisting of active substance, fier or dispersing agent and, if necessary, solvent. latter are suitable for dilution with water. ts can be produced by mixing or blending active nces with a solid carrier. Examples of such are: l, diatomaceous earth, kaolin, bentonite, calcium rate, boric acid, tricalcium phoshate or also sawpowdered cork, charcoal and other materials of ble origin. On the other hand, the carriers can be mated by means of a volatile solvent. Dusts and can be suspended in water by the addition of wetting and protective colloids and so used as sp y powders for aqueous suspensions can be prepared both from liquid and solid active compounds. However liquid active substances or solid active substances are more suitable for the preparation of liquid concentrates or of wettable powders of higher concentration respectively. The various forms of applicaion can be adapted to the intended use in the usual way by the addition of substances which improve the distribution, the adhesive properties, resistance to rain, and, possibly, the resorption. Such substances are: e.g. fatty acids, resins, wettingagents, glue,

casein or alginates. In the same way, the biological activity can be increased or amplified by the addition of substances which have a bactericidal or fungicidal action or of substances which also influence the growth of plants, as well as by combination with fertilizers.

The concentration of active agent, will, of course, vary as will the rate of application depending upon the efiect desired. In general, however, the active concentration will be between about 1% and by weight of the formulation and will be applied to the plant at a rate sufficient to exert a plant response effect. Actual tests show these agents to be effective at application rates as low as about 1 pound per acre, but the usual rate of application will be between about 3 and 15 pounds per acre. A higher rate of application can, of course, be used where local conditions warrant.

The following examples are given to more fully illustrate the invention.

A. PREPARATION OF THE COMPOUNDS Example I .N,N-bis-(sec-butyl -N,N'-bis-(2-hydroxypropyl)-p-phenylenediamine One hundred g. (1.73 moles) propylene oxide is added over a two-hour period to 330 g. (1.5 moles) N,N'-bis- (secbutyl)-p-phenylenediamine placed in a 0.5 gal. stirred autocalve at 180200 C. The maximum autogenous pressure is p.s.i.g. The stirring is continued for an additional four hours at 190 C. while the pressure drops to 5 to 10 p.s.i.g. The reaction product is fractionated by vacuum distillation and N,N'-bis-(sec-butyl)-N,N'- bis-(Z-hydroxypropyl)-p-phenylenediamine, a brownish viscous oil, is obtained at C. at 0.4 mm. Hg pressure. (Cale: 71.4% C, 10.8% H, and 8.3% N. Found: 71.0% C, 10.5% H, and 8.3% N.) Also present in the reaction mixture is N,N'-di-(sec-butyl -N-2-hydroxypropyl-p-phenylenediamine which is a brown, viscous oil, B.P. 140 C. at 0.4 mm. Hg pressure. The disubstituted product is also obtained in 100% yield by the same procedure using 2 moles of propylene oxide per mole of N,N'-bis-(secbutyl)-p-phenylenediamine.

Example 2.N,N'-bis-(sec-butyl)-N,N'-bis-(2-lzydr0xyethyl) -p-phenylenediamine 1.3 moles of ethylene oxide is reacted with 1.0 mole of N,N'-bis-(sec-butyl) -p-phenylenediamine in accordance with the procedure of Example 1. A yield of 26% of N ,N '-bissec-butyl -N,N '-bis- 2-hyd roxyethyl) -p-phenylenediamine is isolated by fractionation of the crude reaction product.

N,N'-bis-(sec-butyl) N,N bis-(2-hydroxyethyl)-pphenylenediamine is a brownish solid, B.P. 193 C. at

0.15 mm. Hg pressure, M.P. 73 C. (from n-hexane).

This product isobrtained by the same procedure as described -for Example 1 using 2.2 moles of ethylene oxide per mole of N,N'-bis[3'(5-methyl)heptyH-p-phenylenediamine. The crude product, obtained in 96% yield, is fractionated to isolate the pure N,N'-bis-[5-(methyl) heptyl] -N,N'-bis(2-hydroxyethyl ).-p-phenylenediamine in 73% yield. It is a viscous brownish oil boiling 230 C. at 0.1 mm. Hg pressure Calc.: 74.3% C and 6.6% N.

Found: 74.2% and 6.67% N. The absence of--NH" group and the presence of --OH groupis confirmed by infrared analysis; 1

Example Ir-Reaction product of N ,N"-bis[3-(5-methyl)- heptyl]rp-phenylenediamine*with 5.8 moles ethylene oxide Y The :product is obtained iii-100% crude yield by essentially the same procedure'used in Example 1 by reacting 5.8 moles of ethylene oxide withone mole of'N,N'-bis 3 5 -methyl) heptyl] -p-phenylenediamine; The product is a brown viscous oil.

Example 5.Reaction product of N-phenyl-N-cyclohexyl-p-phenylenediamine with four moles of ethylene oxide To a mixtureof 133 0.5 male of N-phenyl-N cyclohexyl-p-phenylencdiamine and g. (0.1 mole) of triethylamine held at 190 to 200 C.-.in a 1 gal. autoclave is added with stirring 88 g. (2.moles) of ethylene oxide. As the reaction proceeds, the addition of ethylene oxide is adjusted so that the pressure does not exceed 120 p.s.i'.g.

After all thexethylenevoxideisadded, stirring iscontinued until the :pressure drops'to about p.s.i.g.:and the triethylamine is then distilled off. The distillation'residuc in the autoclave is the crude reaction product'consisthmg of a mixture of'compounds' having the structure and B." EVALUATIONOF AGENTS Example 6.-Herbicide-pre-em'ergence and postemergence contact kill A- 5% by weight xylene emulsion concentrate of N,N'- di-sec-butyl-N,N'-bis(2 hydroxypropyl) p phenylenediarnine wasrprepared and for prev-emergence testing used to treat soil surface in which was planted seedsof weeds and crops. For post-emergence contact tests, weeds and crops four. to eight" inches highwere' treated with the 1 All rates of application baseclson active ingredient.

Example '7.'-Desiccant' activity a The emulsion of Example 6 was emulsified with water. as carrier and sprayed onto' beanfoliage at a rate of 5 lbs/acre."Desiccaintactivity was indicated 'by 75% of foliage burn.

Example 8.l-Herbicidercontact kill A formulation of 10% by weight of N;'N'-di-sec'-butyl- N-2-hydroxyethyl p-phenylenediamine in 'isophorone with 10%-by weight ofa surfactant (ablend ofra non-ionic and .sulfonate type surtactant) was evaluatednagainst weeds andcropss as described in'iExample. 6. The 'data follow:

TABLE II. CONTACT KILL EFFECTS 10F" N,N'-DI-SEC-' BUTYL-N-2-HYDROXYETHYL-P-PHENYIiENEDIAMINE Percent kill Rate/acre Weed or crop 10 lbs Crabgrass 1 100 Foxtail 1 90-100 5 lbs Crabgrass- 90' Lamb's-quartet. 100 Foxtail Spinach 60 1 Some regrowth.

Example 9.+Herbicide'contact kill At Sibsfiacrexapplied as an emulsionconcentrate of 10% by weight in butyl alcohol with 10% by weight'of isooctyl phenyl polyethoxy' ethanolas surfactantxand under the test'conditions of. Example 6, N',N'-di-tsecabutyl-- N,N-bis(2-hydroxyethyl)-p phenylenediamine gave 60% kill of foxtail and 50% kill-of lambs-quarter;

' Example 10.-Herbicidepre-emergencelenedialnine was sprayed onto Amaranthus vweed at 10' lbs/acre and 100% kill was Obtained-Q:

Example 11.e-Herbicidw-pre emergence Weed seedswere'planted in soil-treated at'l0 lbs./ acre with a 10% .by weightacetone emulsion of N;N'-bis'-[3-- 5-methyl)heptyl] -N 2 .l hydroxypropyl p phenylenevdlanllfle. Pie-emergence; herbicide activity was indicated by 75%' kill off foxtail; kill of crabgrass, 80% kill, of-lambs-quarten 70% killfof' purslane; 'and '60%' kill of pigweed;

Example 12:Jirbicide-pre*emergence and contact 1 i A 10% by weightemulsion concentrate of N-phenyl- N'-cyclohexyl-N'-2-hydroxyethyl-p phenylenediamine in diaeetone: alcohol with 10% -by weight of v a polyoxyethylene sorbitol septaoleate surfactant was evaluated asxample 6. The following table gives the data and ts obtained:

Example 13.Def0liant efiecis nulsions of 10% by weight of N,N'-di-sec-butyl-N-2- oxyethyl-p-phenylenediamine in xylene with 10% by ht of an alkyl aryl polyether alcohol surfactant was rsed in water and was applied to the foliage of cotlants at a rate of 5 pounds of active ingredient per A significant defoliant action was evident in 10 will be understood that numerous variations and ifications may be made from the above description examples without departing from the spirit and scope e invention.

claim:

The method of controlling plant growth which coms bringing into contact with said plant in an amount :ient to control said growth, a compound having the .ula

L ew- 2 Ri-N-X e R is a hydrocarbon member selected from the group of alkyl, cycloalkyl, and aryl, said hydrocarbon member containing up to eighteen carbon atoms, Z is a saturated divalent hydrocarbon containing two to three carbon atoms, X is a member selected from the group consisting of H and and n is an integer from 1 to 4.

2. The method of claim 1 wherein X is hydrogen.

3. The method of claim 2 wherein the compound is N,N'-di-sec-butyl-N-2=hydroxycthyl-p-phenylenediamine.

4. The method of claim 2 wherein the compound is N,N'-bis-[3-(5-rnethyl)heptyl]-N 2 hydroxypropyl p phenylenediamine.

5. The method of claim 2 wherein the compound is N phenyl-N'-cyclohexyl-N-2-hydroxyethyl-p-phenylenediamine.

6. The method of claim 1 wherein X is a radical.

7. The method of claim 6 wherein the compound is N,N di-sec-buty1-N,N'-bis-(Z-hydroxypropyl)-p-phenylenediamine.

8, The method of claim 6 wherein the compound is N,N'-di-sec-butyl-N,N-bis(2 hydroxyethyl) p phenylenediamine.

9. The method of claim 6 wherein the compound is N,N'-bis[3-(5-methyl)heptyl]-N,N'-bis(2-hydroxyethyl) p-phenylenediamine.

References Cited in the file of this patent UNITED STATES PATENTS 2,163,166 Wilmanns June 20, 1939 2,348,843 Paul May 16, 1944 2,929,796 Ambelang Mar. 22, 1960 3,121,116 Pawloski Feb. 11, 1964 

1. THE METHOD OF CONTROLLING PLANT GROWTH WHICH COMPRISES BRINGING INTO CONTACT WITH SAID PLANT IN AN AMOUNT SUFFICIENT TO CONTROL SAID GROWTH, A COMPOUND HAVING THE FORMULA 